﻿/*
** uloadlib.c, copyright 2010-2012, Shmuel Zeigerman.
** A modification of Dynamic library loader for Lua
** giving it capability of working with Unicode paths.
** Same license as Lua 5.1.
**
** This modification contains an implementation for Windows only.
*/

/*
** $Id: loadlib.c,v 1.52.1.3 2008/08/06 13:29:28 roberto Exp $
** Dynamic library loader for Lua
** See Copyright Notice in lua.h
**
** This module contains an implementation of loadlib for Unix systems
** that have dlfcn, an implementation for Darwin (Mac OS X), an
** implementation for Windows, and a stub for other systems.
*/


#include <stdlib.h>
#include <string.h>


#define loadlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

#include "lf_string.h"
int LF_LoadFile(lua_State *L, const wchar_t *filename);
const wchar_t* LF_Gsub(lua_State *L, const wchar_t *s, const wchar_t *p,
                       const wchar_t *r);

#undef  LUA_PATHSEP
#define LUA_PATHSEP   L";"

#undef  LUA_PATH_MARK
#define LUA_PATH_MARK L"?"

#undef  LUA_EXECDIR
#define LUA_EXECDIR   L"!"

#undef  LUA_IGMARK
#define LUA_IGMARK    L"-"

#undef  LUA_PATH
#define LUA_PATH      L"LUA_PATH"

#undef  LUA_CPATH
#define LUA_CPATH     L"LUA_CPATH"

#undef  LUA_LDIR
#define LUA_LDIR      L"!\\lua\\"

#undef  LUA_CDIR
#define LUA_CDIR      L"!\\"

#undef  LUA_PATH_DEFAULT
#define LUA_PATH_DEFAULT  \
	L".\\?.lua;"  LUA_LDIR L"?.lua;"  LUA_LDIR L"?\\init.lua;" \
	LUA_CDIR L"?.lua;"  LUA_CDIR L"?\\init.lua"

#undef  LUA_CPATH_DEFAULT
#define LUA_CPATH_DEFAULT \
	L".\\?.dll;"  LUA_CDIR L"?.dll;" LUA_CDIR L"loadall.dll"

/* prefix for open functions in C libraries */
#define LUA_POF		"luaopen_"

/* separator for open functions in C libraries */
#define LUA_OFSEP	"_"


#define LIBPREFIX	"LOADLIB: "

#define POF		LUA_POF
#define LIB_FAIL	"open"


/* error codes for ll_loadfunc */
#define ERRLIB		1
#define ERRFUNC		2

#define setprogdir(L)		((void)0)


static void ll_unloadlib(void *lib);
static void *ll_load(lua_State *L, const wchar_t *path);
static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym);



#if defined(LUA_DL_DLOPEN)
/*
** {========================================================================
** This is an implementation of loadlib based on the dlfcn interface.
** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
** as an emulation layer on top of native functions.
** =========================================================================
*/

#include <dlfcn.h>

static void ll_unloadlib(void *lib)
{
	dlclose(lib);
}


static void *ll_load(lua_State *L, const char *path)
{
	void *lib = dlopen(path, RTLD_NOW);

	if (lib == NULL) lua_pushstring(L, dlerror());

	return lib;
}


static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
	lua_CFunction f = (lua_CFunction)dlsym(lib, sym);

	if (f == NULL) lua_pushstring(L, dlerror());

	return f;
}

/* }====================================================== */



#elif defined(LUA_DL_DLL)
/*
** {======================================================================
** This is an implementation of loadlib for Windows using native functions.
** =======================================================================
*/

#include <windows.h>


#undef setprogdir

static void setprogdir(lua_State *L)
{
	wchar_t buff[MAX_PATH + 1];
	wchar_t *lb;
	DWORD nsize = sizeof(buff)/sizeof(wchar_t);
	DWORD n = GetModuleFileNameW(NULL, buff, nsize);

	if (n == 0 || n == nsize || (lb = wcsrchr(buff, L'\\')) == NULL)
		luaL_error(L, "unable to get ModuleFileName");
	else
	{
		*lb = L'\0';
		LF_Gsub(L, (const wchar_t*)lua_tostring(L, -1), LUA_EXECDIR, buff);
		lua_remove(L, -2);  /* remove original string */
	}
}



static void ll_unloadlib(void *lib)
{
	FreeLibrary((HINSTANCE)lib);
}


static void *ll_load(lua_State *L, const wchar_t *path)
{
	HINSTANCE lib = LoadLibraryW(path);

	if (lib == NULL) pusherror(L);

	return lib;
}


static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
	lua_CFunction f = (lua_CFunction)(intptr_t)GetProcAddress((HINSTANCE)lib, sym);

	if (f == NULL) pusherror(L);

	return f;
}

/* }====================================================== */



#elif defined(LUA_DL_DYLD)
/*
** {======================================================================
** Native Mac OS X / Darwin Implementation
** =======================================================================
*/

#include <mach-o/dyld.h>


/* Mac appends a `_' before C function names */
#undef POF
#define POF	"_" LUA_POF


static void pusherror(lua_State *L)
{
	const char *err_str;
	const char *err_file;
	NSLinkEditErrors err;
	int err_num;
	NSLinkEditError(&err, &err_num, &err_file, &err_str);
	lua_pushstring(L, err_str);
}


static const char *errorfromcode(NSObjectFileImageReturnCode ret)
{
	switch(ret)
	{
		case NSObjectFileImageInappropriateFile:
			return "file is not a bundle";
		case NSObjectFileImageArch:
			return "library is for wrong CPU type";
		case NSObjectFileImageFormat:
			return "bad format";
		case NSObjectFileImageAccess:
			return "cannot access file";
		case NSObjectFileImageFailure:
		default:
			return "unable to load library";
	}
}


static void ll_unloadlib(void *lib)
{
	NSUnLinkModule((NSModule)lib, NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES);
}


static void *ll_load(lua_State *L, const char *path)
{
	NSObjectFileImage img;
	NSObjectFileImageReturnCode ret;

	/* this would be a rare case, but prevents crashing if it happens */
	if (!_dyld_present())
	{
		lua_pushliteral(L, "dyld not present");
		return NULL;
	}

	ret = NSCreateObjectFileImageFromFile(path, &img);

	if (ret == NSObjectFileImageSuccess)
	{
		NSModule mod = NSLinkModule(img, path, NSLINKMODULE_OPTION_PRIVATE |
		                            NSLINKMODULE_OPTION_RETURN_ON_ERROR);
		NSDestroyObjectFileImage(img);

		if (mod == NULL) pusherror(L);

		return mod;
	}

	lua_pushstring(L, errorfromcode(ret));
	return NULL;
}


static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
	NSSymbol nss = NSLookupSymbolInModule((NSModule)lib, sym);

	if (nss == NULL)
	{
		lua_pushfstring(L, "symbol " LUA_QS " not found", sym);
		return NULL;
	}

	return (lua_CFunction)NSAddressOfSymbol(nss);
}

/* }====================================================== */



#else
/*
** {======================================================
** Fallback for other systems
** =======================================================
*/

#undef LIB_FAIL
#define LIB_FAIL	"absent"


#define DLMSG	"dynamic libraries not enabled; check your Lua installation"


static void ll_unloadlib(void *lib)
{
	(void)lib;  /* to avoid warnings */
}


static void *ll_load(lua_State *L, const char *path)
{
	(void)path;  /* to avoid warnings */
	lua_pushliteral(L, DLMSG);
	return NULL;
}


static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
{
	(void)lib; (void)sym;  /* to avoid warnings */
	lua_pushliteral(L, DLMSG);
	return NULL;
}

/* }====================================================== */
#endif



static void **ll_register(lua_State *L, const wchar_t *wpath)
{
	void **plib;
	const char *path = push_utf8_string(L, wpath, -1);
	lua_pushfstring(L, "%s%s", LIBPREFIX, path);
	lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */

	if (!lua_isnil(L, -1))   /* is there an entry? */
		plib = (void **)lua_touserdata(L, -1);
	else    /* no entry yet; create one */
	{
		lua_pop(L, 1);
		plib = (void **)lua_newuserdata(L, sizeof(const void *));
		*plib = NULL;
		luaL_getmetatable(L, "_LOADLIB");
		lua_setmetatable(L, -2);
		lua_pushfstring(L, "%s%s", LIBPREFIX, path);
		lua_pushvalue(L, -2);
		lua_settable(L, LUA_REGISTRYINDEX);
	}

	return plib;
}


/*
** __gc tag method: calls library's `ll_unloadlib' function with the lib
** handle
*/
static int gctm(lua_State *L)
{
	void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");

	if (*lib) ll_unloadlib(*lib);

	*lib = NULL;  /* mark library as closed */
	return 0;
}


static int ll_loadfunc(lua_State *L, const wchar_t *path, const char *sym)
{
	void **reg = ll_register(L, path);

	if (*reg == NULL) *reg = ll_load(L, path);

	if (*reg == NULL)
		return ERRLIB;  /* unable to load library */
	else
	{
		lua_CFunction f = ll_sym(L, *reg, sym);

		if (f == NULL)
			return ERRFUNC;  /* unable to find function */

		lua_pushcfunction(L, f);
		return 0;  /* return function */
	}
}


static int ll_loadlib(lua_State *L)
{
	const wchar_t *path = check_utf8_string(L, 1, NULL);
	const char *init = luaL_checkstring(L, 2);
	int stat = ll_loadfunc(L, path, init);

	if (stat == 0)   /* no errors? */
		return 1;  /* return the loaded function */
	else    /* error; error message is on stack top */
	{
		lua_pushnil(L);
		lua_insert(L, -2);
		lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
		return 3;  /* return nil, error message, and where */
	}
}



/*
** {======================================================
** 'require' function
** =======================================================
*/


static int readable(const wchar_t *filename)
{
	FILE *f = _wfopen(filename, L"r");  /* try to open file */

	if (f == NULL) return 0;   /* open failed */

	fclose(f);
	return 1;
}


static const wchar_t *pushnexttemplate(lua_State *L, const wchar_t *path)
{
	const wchar_t *l;

	while(*path == *LUA_PATHSEP) path++;   /* skip separators */

	if (*path == L'\0') return NULL;   /* no more templates */

	l = wcschr(path, *LUA_PATHSEP);  /* find next separator */

	if (l == NULL) l = path + wcslen(path);

	lua_pushlstring(L, (const char*)path, sizeof(wchar_t) *(l - path));   /* template */
	lua_pushlstring(L, "\0\0", 2);
	lua_concat(L, 2);
	return l;
}


static const wchar_t *findfile(lua_State *L, const char *name,
                               const char *pname)
{
	const wchar_t *path;
	const wchar_t *wname;
	lua_pushstring(L, name);
	wname = utf8_to_utf16(L, -1, NULL);  /* `name' is encoded in UTF-8 */
	wname = LF_Gsub(L, wname, L".", L"\\");
	lua_getfield(L, LUA_ENVIRONINDEX, pname);

	if (lua_tostring(L, -1) == NULL)
		luaL_error(L, LUA_QL("package.%s") " must be a string", pname);

	path = utf8_to_utf16(L, -1, NULL);

	if (path == NULL)
		luaL_error(L, LUA_QL("package.%s") " contains invalid UTF-8", pname);

	lua_pushliteral(L, "");  /* error accumulator */

	while((path = pushnexttemplate(L, path)) != NULL)
	{
		const wchar_t *filename;
		filename = LF_Gsub(L, (const wchar_t*)lua_tostring(L, -1), LUA_PATH_MARK, wname);
		lua_remove(L, -2);  /* remove path template */

		if (readable(filename))   /* does file exist and is readable? */
			return filename;  /* return that file name */

		push_utf8_string(L, filename, -1);
		lua_pushfstring(L, "\n\tno file " LUA_QS, lua_tostring(L, -1));
		lua_remove(L, -2);  /* remove UTF-8 file name */
		lua_remove(L, -2);  /* remove UTF-16 file name */
		lua_concat(L, 2);  /* add entry to possible error message */
	}

	return NULL;  /* not found */
}


static void loaderror(lua_State *L, const wchar_t *filename)
{
	const char* utf8name = push_utf8_string(L, filename, -1);
	luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
	           lua_tostring(L, 1), utf8name, lua_tostring(L, -2));
}


static int loader_Lua(lua_State *L)
{
	const wchar_t *filename;
	const char *name = luaL_checkstring(L, 1);
	filename = findfile(L, name, "path");

	if (filename == NULL) return 1;   /* library not found in this path */

	if (LF_LoadFile(L, filename) != 0)
		loaderror(L, filename);

	return 1;  /* library loaded successfully */
}


static const char *mkfuncname(lua_State *L, const char *modname)
{
	const char *funcname;
	const char *mark = strchr(modname, *LUA_IGMARK);

	if (mark) modname = mark + 1;

	funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
	funcname = lua_pushfstring(L, POF"%s", funcname);
	lua_remove(L, -2);  /* remove 'gsub' result */
	return funcname;
}


static int loader_C(lua_State *L)
{
	const char *funcname;
	const char *name = luaL_checkstring(L, 1);
	const wchar_t *filename = findfile(L, name, "cpath");

	if (filename == NULL) return 1;   /* library not found in this path */

	funcname = mkfuncname(L, name);

	if (ll_loadfunc(L, filename, funcname) != 0)
		loaderror(L, filename);

	return 1;  /* library loaded successfully */
}


static int loader_Croot(lua_State *L)
{
	const char *funcname;
	const wchar_t *filename;
	const char *name = luaL_checkstring(L, 1);
	const char *p = strchr(name, '.');
	int stat;

	if (p == NULL) return 0;   /* is root */

	lua_pushlstring(L, name, p - name);
	filename = findfile(L, lua_tostring(L, -1), "cpath");

	if (filename == NULL) return 1;   /* root not found */

	funcname = mkfuncname(L, name);

	if ((stat = ll_loadfunc(L, filename, funcname)) != 0)
	{
		if (stat != ERRFUNC) loaderror(L, filename);   /* real error */

		lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
		                name, filename);
		return 1;  /* function not found */
	}

	return 1;
}


static int loader_preload(lua_State *L)
{
	const char *name = luaL_checkstring(L, 1);
	lua_getfield(L, LUA_ENVIRONINDEX, "preload");

	if (!lua_istable(L, -1))
		luaL_error(L, LUA_QL("package.preload") " must be a table");

	lua_getfield(L, -1, name);

	if (lua_isnil(L, -1))   /* not found? */
		lua_pushfstring(L, "\n\tno field package.preload['%s']", name);

	return 1;
}


static const int sentinel_ = 0;
#define sentinel	((void *)&sentinel_)


static int ll_require(lua_State *L)
{
	const char *name = luaL_checkstring(L, 1);
	int i;
	lua_settop(L, 1);  /* _LOADED table will be at index 2 */
	lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
	lua_getfield(L, 2, name);

	if (lua_toboolean(L, -1))     /* is it there? */
	{
		if (lua_touserdata(L, -1) == sentinel)   /* check loops */
			luaL_error(L, "loop or previous error loading module " LUA_QS, name);

		return 1;  /* package is already loaded */
	}

	/* else must load it; iterate over available loaders */
	lua_getfield(L, LUA_ENVIRONINDEX, "loaders");

	if (!lua_istable(L, -1))
		luaL_error(L, LUA_QL("package.loaders") " must be a table");

	lua_pushliteral(L, "");  /* error message accumulator */

	for(i=1; ; i++)
	{
		lua_rawgeti(L, -2, i);  /* get a loader */

		if (lua_isnil(L, -1))
			luaL_error(L, "module " LUA_QS " not found:%s",
			           name, lua_tostring(L, -2));

		lua_pushstring(L, name);
		lua_call(L, 1, 1);  /* call it */

		if (lua_isfunction(L, -1))   /* did it find module? */
			break;  /* module loaded successfully */
		else if (lua_isstring(L, -1))   /* loader returned error message? */
			lua_concat(L, 2);  /* accumulate it */
		else
			lua_pop(L, 1);
	}

	lua_pushlightuserdata(L, sentinel);
	lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
	lua_pushstring(L, name);  /* pass name as argument to module */
	lua_call(L, 1, 1);  /* run loaded module */

	if (!lua_isnil(L, -1))   /* non-nil return? */
		lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */

	lua_getfield(L, 2, name);

	if (lua_touserdata(L, -1) == sentinel)      /* module did not set a value? */
	{
		lua_pushboolean(L, 1);  /* use true as result */
		lua_pushvalue(L, -1);  /* extra copy to be returned */
		lua_setfield(L, 2, name);  /* _LOADED[name] = true */
	}

	return 1;
}

/* }====================================================== */



/*
** {======================================================
** 'module' function
** =======================================================
*/


static void setfenv(lua_State *L)
{
	lua_Debug ar;

	if (lua_getstack(L, 1, &ar) == 0 ||
	        lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
	        lua_iscfunction(L, -1))
		luaL_error(L, LUA_QL("module") " not called from a Lua function");

	lua_pushvalue(L, -2);
	lua_setfenv(L, -2);
	lua_pop(L, 1);
}


static void dooptions(lua_State *L, int n)
{
	int i;

	for(i = 2; i <= n; i++)
	{
		lua_pushvalue(L, i);  /* get option (a function) */
		lua_pushvalue(L, -2);  /* module */
		lua_call(L, 1, 0);
	}
}


static void modinit(lua_State *L, const char *modname)
{
	const char *dot;
	lua_pushvalue(L, -1);
	lua_setfield(L, -2, "_M");  /* module._M = module */
	lua_pushstring(L, modname);
	lua_setfield(L, -2, "_NAME");
	dot = strrchr(modname, '.');  /* look for last dot in module name */

	if (dot == NULL) dot = modname;
	else dot++;

	/* set _PACKAGE as package name (full module name minus last part) */
	lua_pushlstring(L, modname, dot - modname);
	lua_setfield(L, -2, "_PACKAGE");
}


static int ll_module(lua_State *L)
{
	const char *modname = luaL_checkstring(L, 1);
	int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
	lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
	lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */

	if (!lua_istable(L, -1))     /* not found? */
	{
		lua_pop(L, 1);  /* remove previous result */
		/* try global variable (and create one if it does not exist) */
		if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
			return luaL_error(L, "name conflict for module " LUA_QS, modname);

		lua_pushvalue(L, -1);
		lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
	}

	/* check whether table already has a _NAME field */
	lua_getfield(L, -1, "_NAME");

	if (!lua_isnil(L, -1))   /* is table an initialized module? */
		lua_pop(L, 1);
	else    /* no; initialize it */
	{
		lua_pop(L, 1);
		modinit(L, modname);
	}

	lua_pushvalue(L, -1);
	setfenv(L);
	dooptions(L, loaded - 1);
	return 0;
}


static int ll_seeall(lua_State *L)
{
	luaL_checktype(L, 1, LUA_TTABLE);

	if (!lua_getmetatable(L, 1))
	{
		lua_createtable(L, 0, 1); /* create new metatable */
		lua_pushvalue(L, -1);
		lua_setmetatable(L, 1);
	}

	lua_pushvalue(L, LUA_GLOBALSINDEX);
	lua_setfield(L, -2, "__index");  /* mt.__index = _G */
	return 0;
}


/* }====================================================== */



/* auxiliary mark (for internal use) */
#define AUXMARK		L"\1"

static void setpath(lua_State *L, const char *fieldname, const wchar_t *envname,
                    const wchar_t *def)
{
	const wchar_t *path = _wgetenv(envname);

	if (path == NULL)   /* no environment variable? */
		lua_pushlstring(L, (const char*)def, sizeof(wchar_t)*(1+wcslen(def)));  /* use default */
	else
	{
		/* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
		path = LF_Gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
		               LUA_PATHSEP AUXMARK LUA_PATHSEP);
		LF_Gsub(L, path, AUXMARK, def);
		lua_remove(L, -2);
	}

	setprogdir(L);
	push_utf8_string(L, (const wchar_t*)lua_tostring(L, -1), -1);
	lua_remove(L, -2);
	lua_setfield(L, -2, fieldname);
}


static const luaL_Reg pk_funcs[] =
{
	{"loadlib", ll_loadlib},
	{"seeall", ll_seeall},
	{NULL, NULL}
};


static const luaL_Reg ll_funcs[] =
{
	{"module", ll_module},
	{"require", ll_require},
	{NULL, NULL}
};


static const lua_CFunction loaders[] =
{loader_preload, loader_Lua, loader_C, loader_Croot, NULL};


LUALIB_API int luaopen_upackage(lua_State *L)
{
	int i;
	/* create new type _LOADLIB */
	luaL_newmetatable(L, "_LOADLIB");
	lua_pushcfunction(L, gctm);
	lua_setfield(L, -2, "__gc");
	/* create `package' table */
	luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
#if defined(LUA_COMPAT_LOADLIB)
	lua_getfield(L, -1, "loadlib");
	lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
#endif
	lua_pushvalue(L, -1);
	lua_replace(L, LUA_ENVIRONINDEX);
	/* create `loaders' table */
	lua_createtable(L, sizeof(loaders)/sizeof(loaders[0]) - 1, 0);

	/* fill it with pre-defined loaders */
	for(i=0; loaders[i] != NULL; i++)
	{
		lua_pushcfunction(L, loaders[i]);
		lua_rawseti(L, -2, i+1);
	}

	lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
	setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
	setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
	/* store config information */
	push_utf8_string(L, L"\\" L"\n" LUA_PATHSEP L"\n" LUA_PATH_MARK L"\n"
	LUA_EXECDIR L"\n" LUA_IGMARK, -1);
	lua_setfield(L, -2, "config");
	/* set field `loaded' */
	luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
	lua_setfield(L, -2, "loaded");
	/* set field `preload' */
	luaL_findtable(L, LUA_REGISTRYINDEX, "_PRELOAD", 4);
	lua_setfield(L, -2, "preload");
	lua_pushvalue(L, LUA_GLOBALSINDEX);
	luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
	lua_pop(L, 1);
	return 1;  /* return 'package' table */
}

